A fusing device includes a pressing member, a belt member to rotate in contact with the pressing member, a nip forming member to support the belt member so that nip areas are formed on the pressing member and the belt member at contacting portions thereto, a heating member disposed away from the nip areas, to heat the belt member, and a tension application member to stiffen the belt member so that the heating member is tightly contacted with the belt member. The heating member includes a plate type heating element which is arranged at an upstream side of the nip areas, and to contact an inner circumference of the belt member, in an advancing direction of the fusing belt. The effective width of then nip areas increases, and the increased pressure is exerted to the nip areas, because the fusing belt enters a location where the nip areas are formed in a heated state. Furthermore, heating efficiency of the fusing belt is increased, because the fusing belt is heated while in a tight contact with the heating member. As a result, fusing performance is enhanced.